Are they getting enough water? Looks like summer sunburn, but could be overwatered and getting root rot.

Thanks. I will check the pot to see if the drainage holes are OK

Yes my basjoo was doing that in April- may. I think it was too much ground water but luckily it sorted it's self out. Even though yours is in a pot I would also check the soil quality and make sure it's not holding a lot of water.

How much sun does it get?

This was in March ...Same thing was happening.

The most recent pic (early Aug)

Thanks guys! I made the hole in the bottom a little bit bigger and I have to admit when I felt the soil it through the bottom was kind of muddy. I always heard that bananas were heavy feeders and I thought that meant that they need a lot of water but now I find out it's fertilizer that they need a lot of ( I think)

Apr-Sept they get direct sunlight between 10 and 3 and filter light ( through surrounding trees) about four hours before and four hours after that. They have to spend 6 to 7 months indoors the rest of the year.